Tilting assembly for lift trucks



Jan. 20, 1959 H. KAGEL TILTING ASSEMBLY FOR LIFT TRUCKS 4 Sheets-Sheet 1Filed Aug. 20, 1956 Jan. 20, 1959 H. KAGEL 2,869,744

TILTING ASSEMBLY FOR LIFT TRUCKS Filed Aug. 20, 1956 I 4 Sheets-Sheet 2Jan. 20, 1959 i'-l. KAGEL TILTING ASSEMBLY FOR LIFT TRUCKS 4Sheets-Sheet a I Filed Aug. 20, 1956 Jan. 20, 1959 H. KAGEL TILTINGASSEMBLY FOR LIFT TRUCKS I 4 Sheets-Sheet 4 Filed Aug. 20, 1956 UnitedStates arena TILTING ASSEMBLY FOR. LIFE TRUCKS Hans.,Kagel,Berg-ischrGladhach, Germany, assignor to VereinigteWestdeutscheWaggonfabriken,Aktiengesellschaft, Koln neutz, Qerrnany,ApplicationlAugust 20; 1956, Serial No. 605,060

Claims priority, applicatiori Germany Augustll, 1955 SfiGlaims.Cl."214672) .The present; invention relates to a. lifttruck. equippedwith a ifter slide which is-guided on a substantially verticalpost-connected to the vehicle frame and which carries the load carrierproper as for instance; a fork or a mandrel.

Lift trucks are; known in which the. guiding post is tiltableaboutaashatt arr nged horizontally: atJthe lower end ot saidypostandflextending; transverse tonthe driving di rection of the vehicle. Ithi way, it is possible forpurnoses of oadinqand unloading-t placethefork-in. a downwardly inclinedposition, whereas. during driving-it.is possible to place the fork. in an upwardlyinclinedpposition. tothereby prevent, the good-s to be transnorted; fromfalling off duringthe braking operation 1 or, When the vehicle: encounters. a sudden push.l-Iowever, this pivotal connection of the guiding post with the vehicleframe brin s. about considerable difficulticsfrom a. structural.standpoint due to the high-load ac ingupon said pivotal connection; Inaddi-tion thereto the, said pivotal. connection is. subject toarelatively quick wean: Due to these difficulties. especiah y. lftt l linc eanhas taken place, the above mentioned ,knownpiyotal connectiondoes notassurethe desired rigidity betweenthe guiding post. andthevehicle frame. Inadditiontheretorthe pivotal connectionof the guidingpost to the. vehicle frame. requires the interposition of hoseconnections; or. other flexible fluidi conveying means between thehydraulic lifting device in'the guiding post and the fluid source on;the vehicle.

. To overcome the above mentioned drawbacks, lift trucks havebeendesicned n which the guiding. mast is rigidly connected to the,vehicle frame; and in. which the fork. or the likeis always,directedupwardly away from the,vehicle. This .tyneoff-lizft. trucks, however.has thedrawback that the loadin and unloading is relatively difficult.Therefore, it hasbeensugtzestedso to desi n the guiding means-onthemed-post that thelifterslide and principal tasks-of suchlifttruckis'possible under-certain difiticulties only.

It is, therefore. an obicct of, the present invention to provide a lifttruck which will overcometheabove mentioned drawbacks.

It; is another object of; this invention toprovide a liftv truck whichwill make it possible to tilt the. load carrier at any-desired levelwithout encountering the difficulties of; the, .lieretofore, knownliittrucks.

ltjs still another object of this. invention-toprovide By making the.post, tiltable in 2,869,744 Patented Jan. 20, 1959 a lift truck of thetype, set forth in the preceding, paragraph in which the tiltingposition of the load. carriermay be varied. t

Still another object of this invention consists in the provisionof alift truck with a load carriertiltable at any desired level, in whichthe tilting operation is effected by a lifting cylinder pistonv systemwhich is simplein constructicn and easily accessible.

These andother objects and advantages of theinvention will appear moreclearly from. the followingspecid cation in connection withtheaccompanying drawings in which: 1

Fig. 1 illustrates a lift truck according to the present invention withthe. load carrier slightly lifted off from the ground.

Fig.2 shows thelift truck of Fig. 1 with the. loadcan rier in picking upposition.

Fig. 3 is a top view ofFig. 1.

.Fig. 4 shows asom-ewhat modified arrangement ofa lift truck with theload. carrier in picking up position.

Fig. 5 is a top view of the lifttruck of,'Fig 4.

Fig. dis a diagrammatic, illustration ofja. hydraulic circuit for useinconnecti'on with the lift truck. according to the invention.

General arrangement The problem underlying thepresent invention namelythe creation of a lifttruck with a,load 1carrier adapted to vention byfixedly connectingtlie guidingpost in a man.-

er known per se tothe vehiclebody, while makingthe entire vehicle bodytogether with the guiding posit. tilta ble about the axis or haft of thewheel set" adjacent the guiding post. To this end; the vehicle body isdisplace.- able substantially in vertical direction relative to thewheel set remote from saijdguiding post, while a lifting device isprovided between said last mentioned wheel set and the vehicle body. Theterm vehicle body is intended to be constructed broadly and to compriseany superstructure of the vehicle. The vehicle body may, for instance,consist of a frame to which the individual units such as guiding post,the wheel setadjacent' said guiding post, motor, transmission, etc. areconnected individually or in groups. However, the vehicle body may alsobe so desi ned that theindividual units are pro-vided withself-supporting casingsand-are-flanged toeach other in a positivemanner. r

Inasmuch as in most-instances a hydraulic lifting device will beemployed for the load carrier, it is advantageous the load about thetilting axisof the vehicle. is higher;

than the oppositely directed'torque of'the weight of the vehicle. insuch an instance, the ve icl'e body is pulled downwardly by the doubleacting lifting deviceat the wheel set remote from the load carrierwhichlast tioned wheel set may be provided with additional counten weights.

The wheel set remote from the guiding post may, for instance, be guidedin a substantially. vertical guide ofth o vehicle body or it may belinked.- tothe-vehicle-body by means of a substantially horizontallevcreretending in-th'c longitudinal direction; of the vehicle.

Structural arrangement Referring now to the drawings in detail and Figs.1 to i wheel set 5. The engine 2 is furthermore adapted through theintervention of gears 6 and 7 to drive a hydraulic pump 8 for feedingthe two hydraulic cylinders 9 and 10. The steering mechanism 11 and thedrivers seat 12 are connected to the vehicle body 1. Fixedly connectedto the front side of the vehicle body 1 by means of screws 13 is aguiding post 14 for the lifter slide 15. The lifter slide 15 carries afork 16. Due to the fact that the drivers seat 12 is connected to thevehicle body 1, it will tilt together with the tilting movement of thevehicle body which tilting movement will be described furtherbelow. Thisfact that the drivers seat tilts together with the vehicle body givesthe operator a sure indication as to the inclined position of thevehicle so that if the vehicle body should be in lifted position, theinclined position of the drivers seat will always remind the driverprior to causing the vehicle to move, to lower the vehicle body. Therear wheel set 17 is in conformity with the showing of Fig. 3 linked tothe vehicle frame 1 by levers 18 and 19 respectively on both sides ofthe chassis. These levers 18 and 19 extend substantially horizontally inthe longitudinal direction of the vehicle. The pivots 20 and 21 of thelevers 18 and 19 are located as closely as possible to the axis of thewheel set 5. The pivots 20 and 21 are so arranged that the distances a(Figs. 1 and 2) of said pivots 20 and 21 from the plane AB through theaxes of the two Wheel sets and 17 measured perpendicular from said planeequal each other when the vehicle body is completely lowered and whenthe vehicle body is completely lifted. In this way, the change in thewheel base, i. e. in the distance between the wheel sets 5 and 17 duringthe tilting movement of the vehicle body 1 about its front wheel set 5will be reduced to a minimum. If the pivots 20, 21 would be located onthe axis of the wheel set 5, no change in the wheel base would occurduring the tilting movement of the vehicle base 1. Such an arrangement,however, would due to lack of space on the wheel set 5 which is beingdriven cause considerable difficulties from the design standpoint. I

The rear ends of the two levers 18 and 19 have co nected thereto acounterweight 22, while a further counterweight 23 is connected to therear end of the vehicle body 1.

Interposed between the wheel set 17 andthe vehicle body 1 is a hydrauliccylinder piston system by means of which the vehicle body 1 can betilted about the axis of the wheel set 5 thereby causing the fork 16 tochange its inclined position. The hydraulic cylinder piston sys tem 10is designed as a double acting cylinder piston system so that it canpress as well as pull. A pulling operation of the cylinder piston system10 may be necessary when'it is intended to tilt back the vehicle bodyafter the fork 16 has been loaded while the vehicle body 1 was in tiltedup position. When the torque of the load on fork 16 about the frontwheel set 5 is higher than the torque of the weight of the vehicle body1 and the counterweight 23, it is necessary that the vehicle body 1 bepulled downwardly by the cylinder piston system 10. The arrangement ofat least a portion of the counterweight on the levers 18 and 19 yields alow position of the center of gravity of the entire vehicle which factis favorable for the driving properties and the stability of the truck.Furthermore, in :this instance it is not necessary to lift thecounterweight by the cylinder-piston system It).

The vertical movement of the lifter slide which is guided by guidingrollers 24 and 25 on the post 14 is effected by thehydraulic cy1inder'9through the intervention of a chain 26 which passes over a return roller27 mounted on the post 14.

The embodiment of Figs. 4 and 5 differs from that of Figs. 1 to 3primarily in that the total counterweight 28 is connected to the rearwheel set 17. The vehicle body 1 is guided relative to the rear wheelset 17 by dovetail shaped vertical guiding means 29 and 30. Theremaining parts corresponding to those of the embodiment shown in Figs.1 to 3 are designated with the same reference numerals as in Figs. 1 to3.

As has been clearly shown in Fig. 6, the driving system and thehydraulic system for the vehicle comprises an internal combustion engine2. This engine drives a hydrostatic pump 3 through a clutch 31 whileconduits 32 and 33 lead from said pump 3 to a control valve 34. Thecontrol valve 34 controls the supply of pressure oil through conduits36, 37, 38, and 39 to the drive motors 4' and 35. The return conduitfrom control valve 34 to the oil reservoir 40 is designated with thereference nu meral 41. The hydrostatic pump draws oil from the oilreservoir 40 through conduit 42.

The internal combustion engine 2 additionally drives through gears 6 and7 a hydraulic pump 8 which draws oil from the oil reservoir 40 through aconduit 43, The pressure oil conveyed by the hydraulic pump 8 to thecontrol valve 45 through conduit 44 may selectively be conveyed througha conduit 46 to the master cylinder 9 for the fork 16 or through theconduit 47 or 48 to the hydraulic cylinder piston system 10 for purposesof tilting the vehicle body. Depending on whether pressure oil isconveyed to the cylinder piston system 10 through conduit 47 or conduit48, the cylinder piston System10 will press the vehicle body 1 upwardlyor pull it down wardly respectively.

As will be evident from the foregoing description, the arrangementaccording to the present invention overcomes all difiiculties heretoforeencountered with lift trucks having a tiltable guiding post. By tiltingthe entire vehicle body in conformity with the present inventionincluding the guiding post, the load carrier may at any desired level bemoved into any desired inclined position. Fur

thermore, the arrangement according to the invention also makes itpossible to design the steering body, i. e. the body'of the wheel setremote from the guiding post, as a one-piece cast body.

It will also be obvious from the foregoing description that the mastercylinder piston system is of a simple construction and is easilyaccessible as to its entirety and also as to its connection to thevehicle body at the rear end thereof inasmuch as at this place neitherthe vehicle body itself nor other elements within the vehicle bodyinterfere with the accessibility.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular constructions shown in the drawings butalso comprises any modifications within the scope of the appendedclaims.

What I claim is:

1. In combination in a lift truck having a vehicle body: a first axlewith a pair of wheels, said vehicle body being pivotally connected tosaid first axle so as to be tiltable about the same, an upwardlyextending post fixedly connected to said vehicle body near said firstpair of wheels, at lifter slide movably mounted on said post andincluding load-supporting means, a second axle spaced from said firstaxle in longitudinal direction of said truck and provided with a secondpair of wheels, link arm means pivotally linking said rear axle to saidvehicle body near said first axle, and fluid operable cylinder pistonmeans linked to said second axle and said vehicle body for selectivelytilting said vehicle body about said first axle from a lowered positioninto a maximum lifted position and vice versa, said link arm means whensaid vehicle body is in its lowered position forming with the planepassing through the axes of said two axles an angle which issubstantially equal to the angle formed by said plane with said link armmeans when said vehicle body is in its maximum lifted position.

2. In combination in a lift truck having a vehicle body: a first axlewith a pair of wheels, said vehicle body being pivotally connected tosaid first axle so as to be tiltable about the same, an upwardlyextending post fixedly connected to said vehicle body near said firstpair of wheels, a lifter slide movably mounted on said post andincluding load-supporting means, a second axle spaced from said firstaxle in longitudinal direction of said truck and provided with a secondpair of wheels, link means pivotally linking said rear axle to saidvehicle body near said first axle, and fluid operable cylinder pistonmeans linked to said second axle and said vehicle body for selectivelytilting said vehicle body from its normal position into a liftedposition and vice versa, said load-supporting means having itsload-supporting surface pointing upwardly when said vehicle body is inits normal position and having its load-supporting surface pointingdownwardly with the front end thereof close to the ground when saidvehicle body is in its lifted position.

3. In combination in a lift truck having a vehicle body: a first axlewith a pair of wheels, said vehicle body being pivotally connected tosaid first axle so as to be tiltable about the same, an upwardlyextending post fixedly connected to said vehicle body near said firstpair of wheels, a lifter slide movably mounted on said post andincluding load-supporting means, a second axle spaced from sad firstaxle in longitudinal direction of said truck and provided with a secondpair of wheels, link means pivotally linking said rear axle to saidvehicle body near said first axle, a first counterweight connected tosaid second axle, a second counterweight connected to that end of thevehicle body which is adjacent said second axle, and fluid operablecylinder piston means linked to said second axle and said vehicle bodyfor selectively tilting said vehicle body about said first axle.

4. In combination in a lift truck having a vehicle body: a first axlewith a pair of wheels, said vehicle body being pivotally connected tosaid first axle so as to be tiltable about the same, an upwardlyextending post fixedly connected to said vehicle body near said firstpair of wheels, a lifter slide movably mounted on said post andincluding load-supporting means, a second axle spaced from said firstaxle in longitudinal direction of said truck and provided with a secondpair of wheels, link means pivotally linking said rear axle to saidvehicle body near said first axle, a counterweight representing thetotal counterweight and being connected to said second axle, and fluidoperable cylinder piston means linked to said second axle and saidvehicle body for selectively tilting said vehicle body about said firstaxle.

5. In combination in a lift truck having a vehicle body: a first axlewith a pair of wheels, said vehicle body being pivotally connected tosaid first axle so as to be tiltable about the same, an upwardlyextending post fixedly connected to said vehicle body near said firstpair of wheels, a lifter slide movably mounted on said post andincluding load-supporting means, a second axle spaced from said firstaxle in longitudinal direction of said truck and provided with a secondpair of wheels, link means pivotally linking said rear axle to saidvehicle body near said first axle, and fluid operable cylinder pistonmeans interposed between and operatively connected to said link meansand said body for selectively tilting said vehicle body from its normalposition into a lifted position and vice versa, said load-supportingmeans having its load-supporting surface pointing upwardly when saidvehicle body is in its normal position and having its load-supportingsurface pointing downwardly with the front end thereof close to theground when said vehicle body is in its lifted position.

References Cited in the file of this: patent UNITED STATES PATENTS2,439,139 LeTourneau Apr. 6, 1948 2,623,653 Frarnhein Dec. 30, 19522,684,165 Hill July 20, 1954 2,693,250 Barrett Nov. 2, 1954

